Mattress



FIG. 1 is an isometric view of a front, top, and right side of an ornamental design for a mattress;

FIG. 2 is a front elevational view of the mattress of FIG. 1, of which the rear elevational view is a mirror image;

FIG. 3 is a right side elevational view of the mattress of FIG. 1, of which the left side elevational view is a mirror image;

FIG. 4 is a top plan view of the mattress of FIG. 1;

FIG. 5 is a bottom plan view of the mattress of FIG. 1; and,

FIG. 6 is an isometric view of a front, top, and right side of another embodiment of an ornamental design for a mattress.

It is understood that the dash-dash-dash broken lines represent a pattern on the surface of the mattress or environmental structure that form no part of the claimed design. The dash-dot-dash broken lines on the mattress of FIGS. 1-5 depict a mattress with a symbolic break in its length and width. The dash-dot-dash broken lines on the mattress of FIG. 6 depict a mattress with a symbolic break in its length, width, and height. The appearance of any portion of the article between the break lines forms no part of the claimed design. 

CLAIM The ornamental design for a mattress, as shown and described. 